EP0039103B1 - Gammakamera unter Anwendung einer Szintillationslichtverstärkungseinrichtung - Google Patents

Gammakamera unter Anwendung einer Szintillationslichtverstärkungseinrichtung Download PDF

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Publication number
EP0039103B1
EP0039103B1 EP81200402A EP81200402A EP0039103B1 EP 0039103 B1 EP0039103 B1 EP 0039103B1 EP 81200402 A EP81200402 A EP 81200402A EP 81200402 A EP81200402 A EP 81200402A EP 0039103 B1 EP0039103 B1 EP 0039103B1
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EP
European Patent Office
Prior art keywords
intensifier
scintillation
camera
modules
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81200402A
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English (en)
French (fr)
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EP0039103A1 (de
Inventor
Michel Jatteau
Pierre Lelong
Jean Pergrale
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Laboratoires dElectronique Philips SAS
Koninklijke Philips NV
Original Assignee
Laboratoires dElectronique et de Physique Appliquee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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Application filed by Laboratoires dElectronique et de Physique Appliquee, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Laboratoires dElectronique et de Physique Appliquee
Publication of EP0039103A1 publication Critical patent/EP0039103A1/de
Application granted granted Critical
Publication of EP0039103B1 publication Critical patent/EP0039103B1/de
Expired legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
    • G01T1/164—Scintigraphy
    • G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
    • G01T1/1642—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
    • G01T1/164—Scintigraphy
    • G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
    • G01T1/1645—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using electron optical imaging means, e.g. image intensifier tubes, coordinate photomultiplier tubes, image converter

Definitions

  • the present invention relates to a scintillation camera with a locator provided with a scintillation intensifier.
  • the entry window of the intensifier tube given its diameter, is generally convex and thick so that the scintillator crystal pressed against this window must itself have a convex face and the scintillating points are distant from the photocathode.
  • the photocathode as well as the screen of the intensifier tube must have a great uniformity of photoelectric properties on their surface so that the intensification of light is itself uniform on the surface and does not distort the indications of the locator both with regard to the position of the barycenter and the value of the energy measured.
  • British patent GB-A-2,016,206 describes a scintillation camera in which the scintillator is in the form of a blade with parallel faces and is associated with an image intensifier having a curved (or flat but metallic entrance window but including a collimator; and operating without image reduction.
  • This tube has many of the drawbacks mentioned above relating to the uniformity of photocathode and large screen and other drawbacks related to the shape of the entrance window. such as loss of spatial resolution in the case of the curved window and non-interchangeability of the collimator as a function of the desired performance.
  • the dimensions of such a tube are necessarily limited for technological reasons, which results in a limitation of the dimensions of the useful field of cameras.
  • the solution to this problem of field limitation, indicated in this patent, which consists in juxtaposing several cameras of the same principle as described below. - above has the major drawback of having large blind zones in the useful field; moreover, this solution is complex and expensive to produce.
  • the invention relates to a scintillation camera for detecting X or gamma photons which comprises the same main constituent elements as the cameras mentioned above, namely in order in the direction of propagation of the radiation creating the scintillations, a single scintillator crystal, preferably a window for protecting said crystal transparent to scintillation radiation, a light intensifier, a light dispersing optical guide, a scintillation locator formed by a network of photodetectors whose input faces are opposite the optical guide and circuits connected to said photodetectors so as to produce electrical coordinate signals representing the spatial coordinates of the points of interaction between X or gamma rays and said scintillator crystal as well as a display device serving to represent said electrical signals in the form of light points distributed in a plane, the scintillator crystal, the protective window, the light intensifier, and the optical guide each having the shape of a blade with parallel faces and being pressed in said order against each other, characterized in that said light intensifier
  • the design of said constituent elements of the camera thus proposed is such that it tends to remedy the drawbacks and difficulties mentioned above.
  • the scintillator crystal in the presence of the intensifier, retains a shape of blade with parallel and flat faces whose diameter is not limited by the detection system.
  • the intensifier is designed so that the intensification is almost uniform over the entire surface of the scintillator crystal and has little or no image reduction on its screen.
  • the photoelectric image of each scintillation appears with less geometric distortions and the locator can include a large number of photodetectors, as in the Anger camera.
  • the intensifier can take any surface dimensions in relation to those chosen for the scintillator.
  • this scintillation intensifier consisting of a mosaic of identical independent modules, each having a parallel entry face and one exit face, these modules are juxtaposed and form a blade with parallel faces, the entry face provided with photocathodes. is optically coupled to the exit face of the scintillator crystal via its transparent protection window and the exit face of which is fitted with screens is optically coupled to the event locator.
  • These modules each consist of a tube chosen from those which on the one hand have a photocathode spectral sensitivity in good correspondence with the emission spectrum of the scintillator and on the other by a screen of great speed and having a spectral emission in good correspondence with the sensitivity of the photodetectors.
  • the detection surfaces of these diode tubes have various geometric shapes but, preferably in a circular shape, they are chosen to be polygonal, hexagonal or square, for example, so that they can be joined and form an almost detection surface. keep on going.
  • each intensifier module is a proximity focusing diode tube comprising a photocathode and an anode screen, the locator, taking into account the relatively small gain of the intensifier, being preferably produced from dynode photomultipliers.
  • each module consists of two inversion tubes of magnification image-1 placed one above the other, the screen of the first having a curve of relative spectral sensitivity similar to that of the photocathode of the second.
  • the intensification gain being higher than according to the first variant, the locator can be produced using semiconductor photodetectors with lower gain than the dynode photomultipliers.
  • the intensifier modules are of the wafer type of microchannels with electronic secondary emission and proximity focusing.
  • the intensification gain is large enough for the locator to be produced with semiconductor photodetectors rather than with dynode photomultipliers.
  • FIG. 1 represents a camera according to the invention, seen from the front from the locator side.
  • the dotted circle 10 and the circle 11 represent the contours of the scintillator and of the light guide respectively seen from the locator side.
  • the photodetectors constituting the latter form an array 12 and are placed facing the crystal on the light guide.
  • the photodetectors are arranged, for example, in a hexagonal configuration around a central photodetector.
  • Each solid circle represents the entry face of one of these photodetectors.
  • the one designated by 13a corresponds to the central photodetector; 13b, 13c, 13d, denote the photo detectors aligned along the diameter AB with 13a and each belonging to one of the hexagons.
  • two photodetectors symmetrical with respect to 13a and arranged on the diameter AB have the same number.
  • FIG 2 shows the cross section of the inlet along the diameter AB of Figure 1 of a first variant of the camera.
  • the scintillator bears the number 19, a window for protecting the scintillator in pyrex glass, for example, the number 20 and the optical guide the number 22.
  • the optical guide is placed below the scintillator crystal but, between the crystal provided with its protective window and the guide is placed a light intensifier 21 with parallel faces covering the entire surface of the scintillator 19 and consisting of juxtaposed elements some of which, seen in section along the diameter AB are respectively 21a, 21b, 21 c , 21 d , 21 e .
  • each of these modules is of the proximity focusing photodiode type and consists of a photocathode facing the scintillator crystal and a screen.
  • these photocathode and screen are respectively 17 and 18.
  • the photocathode and screen surfaces of these modules are regular polygonal, for example, hexagonal or square, so that these modules are joined.
  • the useful field of the camera is limited by the diaphragm 16 disposed facing the scintillator crystal 19. In this figure, we find, arranged on the face 23 of the light guide 22, all of the photodetectors 13a, 13b, 13c, 13d constituting the scintillation locator.
  • these photodetectors are photomultipliers with high gain dynodes.
  • the intensifier modules have, in this variant as in all the others, a spectral sensitivity in correspondence with the emission spectrum of the scintillator.
  • the sensitivity spectrum of the photodetectors is in correspondence with the spectrum of the light emitted at the output of the intensifier.
  • the scintillator is a crystal in sodium iodide (1 N a ) doped with blue-emitting Thallium (wavelength centered on 410 nm (4,100 ⁇ )); the photocathode of the intensifier is of the bialcaline type; its screen is a P16 type phosphor emitting in blue.
  • the cathodes of the photomultipliers of the locator being of the bialcaline type.
  • the wavy arrow 15 represents the arrival in the scintillator of a photon y which causes at point P a scintillation which radiates for example along rays such as rays 14a, 14b, 14c, 14d.
  • the photons transported by these rays are intensified in the intensifier modules 21a to 21e whence results at the output of these modules for the corresponding scintillation n bright points such as 9a, 9b, 9c, 9d which in turn radiate towards the photodetectors 13a to 13d of the locator, which determines the coordinates of the scintillation point P from those of said n bright points, the spatial resolution then being improved in a ratio of as the theory indicates (see the article already cited by Lansiart et al).
  • FIG 3 shows the section along the diameter AB of Figure 1 of the input of a second variant of the camera.
  • the light intensifier 21 comprises along the diameter AB the modules 21a, 21b, 21c, 21d, 21e.
  • Each of these modules has two superimposed stages in the form of two inverting image intensifier tubes (negative magnification) connected in cascade.
  • these tubes are respectively 24 and 25.
  • the photocathode and screen of the tube 24 are respectively 26 and 27 and those of the tube 25 respectively 28 and 29. In these photocathode tubes and screen have geometries and surfaces substantially therefore equal are of magnification close to -1.
  • each intensifier module Due to the double inversion within each module, the magnification resulting from the intensifier is close to 1 and appears, on all the output screens, such as 29, a direct view of the scintillation at the exit of the scintillator crystal. . It goes without saying that the two stages of each intensifier module can have magnifications different from -1 and opposite to each other and also that the two stages can be included in the same tube. In addition, the spectral sensitivities of photocathode and screen are similar for the elements coupled between them such as 27 and 28 so that the conversion yields are maximum. Given the significant gain of the light intensifier, the locator can be produced using photodetectors having a relatively low gain.
  • These photodetectors are for example photodiodes made up of semiconductor wafers. These plates deposited on the light guide 22 appear in section along the diameter AB under the numbers 13a, 13b, 13c, 13d. In this figure 3, is indicated as in figure 2 the detection of the scintillation point P.
  • FIG. 4 shows in section along the diameter AB a third variant of the camera.
  • the constituent elements have the same numbers as in FIGS. 2 and 3.
  • the constituent modules of the intensifier are of the wafer type of microchannels with electronic secondary emission.
  • the wafer relating to the module 21 b is represented under the number 32 while the photocathode and the screen are represented under the numbers 30 and 31 respectively.
  • the locator can be made using photodiodes made up of semiconductor material plates. These plates in section along the diameter AB bear the numbers 13a, 13b, 13c, 13d. In this figure is indicated as in Figures 2 and 3, the detection of the scintillation point P.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Measurement Of Radiation (AREA)
  • Nuclear Medicine (AREA)

Claims (7)

1. Gammakamera zur Detektion von Röntgen-oder Gammaphotonen mit einem Szintillationskristall (19), vorzugsweise einem Schutzfenster (20) des Kristals, das für die SzintiHationsstrahlung transparent ist, einem Lichtverstärker (21), einem Szintillationsortbestimmer in Form eines Netzes (12) von Fotodetektoren (31a...d), deren Eingangsflächen dem optischen Leiter zugewandt sind, und von derart mit den Fotodetektoren verbundenen Schaltkreisen, dass sie elektrische Koordinatensignale erzeugen, die die räumlichen Koordinaten der Wechselwirkungspunkte zwischen den Röntgen- oder Gammastrahlen und dem Szintillationskristall darstellen, sowie mit einer Anzeigeeinrichtung zum Darstellen der elektrischen Signale in Form von gleichmässig auf eine Ebene verteilten Leuchtpunkten, wobei die genannten Elemente in der Strahlungsfortpflanzungsrichtung angeordnet sind und weiter der Szintillationskristal (19), das Schutzfenster (20), des Lichtverstärker (21) und der optische Leiter (22) je die Form einer Platte mit parallel verlaufenden Flächen aufweisen und in der genannten Reihenfolge aneinander gelegt sind, dadurch gekennzeichnet, dass der Lichtverstärker (21) aus einem Mosaik gleicher Moduln (21a...e) mit einer Vergrösserung nahe bei 1 besteht, die unabhängig und lückenlos nebeneinander angeordnet sind, sich zwischen den parallel verlaufenden Flächen des Verstärkers erstrecken und je an der Szintillationsseite eine Fotorkathode (17, 26, 30) und an der optischen Leiterseite eine Schirm (18, 29, 31) enthalten.
2. Gammakamera nach Anspruch 1, dadurch gekennzeichnet, dass jeder Modul (21a...e) des Verstärkers (21) eine Diodenröhre mit Nahfokussierung ist und dass der Ortsbestimmer vorzugsweise aus einem Netz (12) von Dynodenfotovervielfachern besteht.
3. Gammakamera nach Anspruch 1, dadurch gekennzeichnet, dass jeder Modul (21a...e) des Verstärkers (21) zwei über einander angebrachte Stufen (24, 25) enthält, die je aus einer Bildverstärkerröhre bestehen, wobei der Schirm (27) der erste Stufe (24) mit der Fotokathode (28) der zweiten Stufe (25) zusammenfält, und dass der Ortsbestimmer vorzugweise aus einem Netz von Fotodioden jeweils in Form von Halbleiterplatten besteht.
4. Gammakamera nach Anspruch 3, dadurch gekennzeichnet, dass die Vergrösserung dieser Stufen (24, 25) negativ und zu einander invers sind.
5. Gammakamera nach Anspruch 1, dadurch gekennzeichnet, dass jeder Modul (21a...e) des Verstärkers (21) eine Fotokatode (30), eine Mikrokanalplatte (32) mit Sekundärelektronenemission und einen Schirm (31), enthält, und dass der Ortsbestimmer vorzugweise aus einem Netz von Fotodioden in Form von jeweils Halbleiterplatten besteht.
6. Gammakamera nach einem Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Moduln (21a...e) des Verstärkers einen vieleckigen Aussenumriss haben.
7. Gammakamera nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass über dem Spalt zwischen aktiven Teilen der Verstärkermoduln das Schutzfenster (20) mit einer in Richtung auf den Szintillationskristall (19) reflektierenden Schicht (8) bedeckt ist.
EP81200402A 1980-04-29 1981-04-08 Gammakamera unter Anwendung einer Szintillationslichtverstärkungseinrichtung Expired EP0039103B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8009669 1980-04-29
FR8009669A FR2481466A1 (fr) 1980-04-29 1980-04-29 Camera a scintillations avec localisateur munie d'un intensificateur de scintillations

Publications (2)

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EP0039103A1 EP0039103A1 (de) 1981-11-04
EP0039103B1 true EP0039103B1 (de) 1985-02-06

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ID=9241487

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EP81200402A Expired EP0039103B1 (de) 1980-04-29 1981-04-08 Gammakamera unter Anwendung einer Szintillationslichtverstärkungseinrichtung

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US (1) US4438334A (de)
EP (1) EP0039103B1 (de)
JP (1) JPS57571A (de)
CA (1) CA1190981A (de)
DE (1) DE3168731D1 (de)
FR (1) FR2481466A1 (de)
IL (1) IL62719A (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2567276B1 (fr) * 1984-07-06 1988-02-19 Labo Electronique Physique Perfectionnement apporte a une camera pour la detection de rayonnements x et g, camera dont le bloc scintillateur possede une fenetre d'entree formee d'une structure-support mecaniquement rigide et tres faiblement absorbante auxdits rayonnements
US5521386A (en) * 1995-02-09 1996-05-28 The United States Of America As Represented By The Secretary Of The Air Force Gamma ray camera method and apparatus
JP5680943B2 (ja) * 2010-11-16 2015-03-04 キヤノン株式会社 シンチレータ、放射線検出装置および放射線撮影装置
DE102011077056A1 (de) * 2011-06-07 2012-12-13 Siemens Aktiengesellschaft Strahlungsdetektor und bildgebendes System

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Publication number Priority date Publication date Assignee Title
FR2304928A1 (fr) * 1975-03-18 1976-10-15 Commissariat Energie Atomique Dispositif de localisation de phenomenes lumineux
US4221967A (en) * 1978-03-10 1980-09-09 Diagnostic Information, Inc. Gamma ray camera

Also Published As

Publication number Publication date
US4438334A (en) 1984-03-20
FR2481466B1 (de) 1982-10-01
EP0039103A1 (de) 1981-11-04
DE3168731D1 (en) 1985-03-21
IL62719A0 (en) 1981-06-29
JPS57571A (en) 1982-01-05
CA1190981A (en) 1985-07-23
FR2481466A1 (fr) 1981-10-30
IL62719A (en) 1983-11-30

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